let map1 =  new Map()
map1.set('key1','val1')
map1.set('key2','val2')
map1.set('key3','val3')
let key4 = {
  school:"jimei"
}
map1.set(key4,['fujian','xiamen'])
console.log(map1.get(key4))
console.log(map1.has('key3'))
console.log(map1.size)
//map1.clear()
console.log(map1)

